Catalyst for preparing 1,3-alkanediol from epoxide derivative

ABSTRACT

A process for preparing an 1,3-alkanediol through carbonylation of an epoxide derivative includes the steps of (a) reacting an epoxide derivative with alcohol and carbon monoxide in a solvent at a temperature from about 30 to about 150° C. and at a pressure from about 50 to about 3000 psig in the presence of a catalyst system including an effective amount of a cobalt catalyst and an effective amount of a promoter to afford a reaction mixture including a 3-hydroxyester or derivative thereof in an amount of from 2 to about 95% by weight, (b) separating the reaction product and solvent from the catalyst and promoter, (c) reacting said reaction product and solvent with hydrogen at a temperature from about 30 to about 350° C. and at a pressure from about 50 to about 5000 psig in the presence of a catalyst system for hydrogenation to prepare a hydrogenation product mixture including a 1,3-alkanediol, and (d) recovering the 1,3-alkanediol from the hydrogenation product mixture.

This is a division of U.S. patent application Ser. No. 10/005,072, filedDec. 7, 2001, which in turn is a continuation-in-part of U.S. patentapplication Ser. No. 09/570,012, filed May 12, 2000, now U.S. Pat. No.6,348,632, the disclosures of which are incorporated herein in theirentirety by reference.

FIELD OF THE INVENTION

The present invention relates to a process for preparing a1,3-alkanediol through carbonylation of an epoxide derivative. Morespecifically, the present invention relates to a process for preparing a1,3-alkanediol, which comprises reacting an epoxide derivative with analcohol and carbon monoxide in the presence of a catalyst systemincluding a cobalt catalyst and a promoter to afford a 3-hydroxyester,and adding hydrogen to the 3-hydroxyester to prepare the 1,3-alkanediol.

BACKGROUND OF THE INVENTION

An epoxide derivative can be easily converted into a difunctionalcompound through carbonylation, which is used as an intermediate forpreparing an organic compound. In particular, a 3-hydroxyesterderivative has two functional groups, and is used as a solvent, a resin,a coating material, a material for medical substances, an intermediatefor preparing alkanediols which are used for preparing polyesters, etc.The alkanediols are used as intermediates for coating materials orsynthetic organic compounds. A 1,3-diol is an example of an alkanediol.As shown in the following scheme, a 1,3-diol is prepared byhydroformylating an epoxide derivative to prepare a 3-hydroxyaldehydederivative and adding hydrogen to the 3-hydroxyaldehyde derivative toconvert the aldehyde groups into alcohol groups.

The scheme for preparing a 1,3-diol set forth above was disclosed inU.S. Pat. Nos. 5,770,776; 5,723,389; and 5,731,478. On the other hand,in a known process for synthesizing a 3-hydroxyaldehyde showing a highselectivity under low temperature and low pressure, there are used acobalt catalyst and phosphine oxide ligand as a promoter. However, whenphosphine oxide ligand is used as a promoter, the recovery andregeneration of the catalyst become complicated.

U.S. Pat. No. 5,770,776 discloses a process for preparing1,3-propanediol comprising the steps of (a) contacting ethylene oxidewith carbon monoxide and hydrogen in a non-water-miscible solvent in thepresence of an effective amount of a non-phosphine-ligated cobaltcatalyst and an effective amount of a catalyst promoter, (b) adding anaqueous liquid to the intermediate product mixture and extracting intothe aqueous liquid a major portion of the 3-hydroxypropanal so as toprovide a first aqueous phase and a first organic phase, (c) separatingthe first aqueous phase from the first organic phase, (d) adding freshnon-water-miscible solvent to the first aqueous phase and extractinginto such solvent a portion of any cobalt catalyst or cobalt-containingderivative thereof present in such aqueous phase, to provide a secondaqueous phase and a second organic phase, (e) separating the secondaqueous phase from the second organic phase, (f) passing the firstorganic phase and the second organic phase to the process step (a), (g)contacting the second aqueous phase with hydrogen, and (h) recovering1,3-propanediol.

U.S. Pat. Nos. 5,723,389 and 5,731,478 disclose a process for preparingan alkanediol comprising the steps of (a) contacting an ethylene oxidewith carbon monoxide and hydrogen in a non-water-miscible solvent in thepresence of an effective amount of a non-phosphine-ligated cobalt orrhodium catalyst and an effective amount of a cobalt or rhodiumporphyrin promoter, (b) adding an aqueous liquid to the intermediateproduct mixture and extracting into the aqueous liquid a major portionof the hydroxyaldehyde so as to provide an aqueous phase and an organicphase, (c) separating the aqueous phase from the organic phase, (d)contacting the aqueous phase with hydrogen in the presence of ahydrogenation catalyst, and (e) recovering the alkanediol.

U.S. Pat. Nos. 5,135,901 and 4,973,741 disclose another process forobtaining the 3-hydroxyester derivative from the epoxide derivatives. Inthis process, there is synthesized methyl 3-hydroxypropionate fromethylene oxide by using rhodium and ruthenium as catalysts in thepresence of carbon monoxide and alcohol. However, in this process, inspite of the use of expensive catalysts, the yield of the3-hydroxypropionate is as low as 60%, and by-products are produced inconsiderable amounts. Further, there is another known process forobtaining a 3-hydroxyester by hydroesterification of the epoxide. Inthis process also, the yield is as low as 40-60% [(1) Dalcanali, E.;Foa, M. Synthesis 1986, 492. (2) Heck, R. F., J. Am. Chem. Soc., 1963,85, 1460. (3) Eismann, J. L.; Yamartino, R. L.; Howard, Jr. J. F., J.Org. Chem. 1961, 2102.]. The reason why the yield is so low is that theisomerization reaction of the starting material readily occurs.

Meanwhile, U.S. Pat. Nos. 5,310,948 and 5,359,081 relate tocarbonylation of the epoxide, in which the epoxide and carbon monoxideare reacted in the presence of cobalt and pyridine derivatives. Thefinal product is mainly β-lactone, and the by-product is the3-hydroxyester.

In the preparation of 1,3-alkanediols for preparing polyesters, if a3-hydroxyaldehyde is used an intermediate, the quality of the polyesterbecomes lower because of formation of oligomers and acetals asby-products. On the other hand, if a 3-hydroxyester is used anintermediate, the yield will be lower yield and the catalyst cost willbe high.

An effective catalyst system for preparing a 3-hydroxyester derivativefrom an ethylene oxide through hydroesterification has not beendeveloped yet, and a method of obtaining a 1,3-alkanediol in a highyield has not been developed yet.

SUMMARY OF THE INVENTION

One feature of the present invention is the provision of a novel processfor preparing a 1,3-alkanediol, which comprises reacting an epoxidederivative with an alcohol and carbon monoxide in the presence of acatalyst system that includes a cobalt catalyst and a promoter to afforda 3-hydroxyester, and adding hydrogen to the 3-hydroxyester to preparethe 1,3-alkanediol.

Another feature of the invention is the provision of a new catalystsystem for preparing 3-hydroxyesters in a high yield by reacting anepoxide derivative with an alcohol and carbon monoxide, which catalystsystem includes a cobalt catalyst and an imidazole or a derivativethereof as promoter.

A further feature of the invention is the provision of a process forpreparing a 1,3-alkanediol, using a new catalyst system as describedherein.

Still another feature of the invention is the provision of a process forpreparing 1,3-alkanediols at a lower cost by using an imidazole or aderivative thereof as promoter.

In accordance with one aspect of the present invention, there isprovided a process for preparing a 1,3-alkanediol through carbonylationof an epoxide derivative, which includes the steps of (a) reacting anepoxide derivative with an alcohol and carbon monoxide in a solvent at atemperature from about 30 to about 150° C. and at a pressure from about50 to about 3000 psig in the presence of a catalyst system including aneffective amount of a cobalt catalyst and an effective amount of apromoter to afford a reaction product including at least one3-hydroxyester or derivative thereof in an amount from about 2 to about95% by weight, (b) separating the reaction product and solvent from thecatalyst and promoter, (c) reacting the reaction product and solventwith hydrogen at a temperature from about 30 to about 350° C. and at apressure from about 50 to about 5000 psig in the presence of a catalystsystem for hydrogenation to prepare a hydrogenation product mixtureincluding a 1,3-alkanediol, and (d) recovering the 1,3-alkanediol fromthe hydrogenation product mixture.

In accordance with another aspect of the present invention, a catalystsystem for preparing a 1,3-alkanediol as described herein is provided.

Other objects, features and advantages of the present invention willbecome apparent to those skilled in the art from the following detaileddescription. It is to be understood, however, that the detaileddescription and specific examples, while indicating preferredembodiments of the present invention, are given by way of illustrationand not limitation. Many changes and modifications within the scope ofthe present invention may be made without departing from the spiritthereof, and the invention includes all such modifications.

DETAILED DESCRIPTION OF THE INVENTION

Korean patent application number 2000-5357, filed on Feb. 3, 2000 andentitled “Process for Preparing 1,3-Alkanediol from Epoxide Derivative”is incorporated by reference herein in its entirety.

The present inventors have developed a process for preparing a1,3-alkanediol in a high yield by synthesizing a 3-hydroxyester as anintermediate from an epoxide derivative through hydroesterification, andthen reacting the 3-hydroxyester with hydrogen and a catalyst system forhydrogenation.

The present invention thus relates to a process for preparing a1,3-alkanediol through carbonylation of an epoxide derivative. Anepoxide derivative reacts with an alcohol and carbon monoxide in asolvent at a temperature from about 30 to about 150° C. and at apressure from about 50 to about 3000 psig in the presence of a catalystsystem including an effective amount of a cobalt catalyst and aneffective amount of a promoter to afford a reaction product including atleast one 3-hydroxyester or derivative thereof in an amount from about 2to about 95% by weight. In this invention, this step is called“hydroesterification”. The reaction product and solvent are separatedfrom the catalyst and promoter. The reaction product and solvent reactwith hydrogen at a temperature from about 30 to about 350° C. and at apressure from about 50 to about 5000 psig in the presence of a catalystsystem for hydrogenation to prepare a hydrogenation product mixtureincluding a 1,3-alkanediol. In this invention, this step is called“hydrogenation”. The 1,3-alkanediol is recovered from the hydrogenationproduct mixture.

In the present invention, an effective catalyst system is employed tomaximize the production yield of the 3-hydroxyester when an epoxidederivative undergoes the hydroesterification. The catalyst systemincludes a cobalt catalyst and a catalyst promoter. The cobalt catalystcan be, for example, Co₂(CO)₈, or a mixture of Co₂(CO)₈ and an organiccompound. The organic compound preferably is selected from the groupconsisting of imidazole, pyridine, pyrrole, pyrazine, pyrimidine,piperidine, a derivative thereof, and a mixture thereof. It ispreferable to use an organic compound which is not bonded to a phosphinecompound.

Preferably, an imidazole derivative as shown in the following formula(I) is used as a promoter:

where R₁₄, R₁₅, R₁₆ and R₁₇ independently are hydrogen; branchedaliphatic hydrocarbon having 3 to 10 carbon atoms; linear aliphatichydrocarbon having 1 to 10 carbon atoms; saturated cyclohydrocarbonhaving 3 to 10 carbon atoms; cycloaliphatic hydrocarbon having 3 to 10carbon atoms; aromatic aliphatic hydrocarbon having 7 to 10 carbonatoms; F; Cl; alkoxy having 1 to 3 carbon atoms; OH; OH group-containingbranched aliphatic hydrocarbon having 3 to 10 carbon atoms; OHgroup-containing linear aliphatic hydrocarbon having 1 to 10 carbonatoms; OH group-containing saturated cyclohydrocarbon having 3 to 10carbon atoms; OH group-containing cycloaliphatic hydrocarbon having 3 to10 carbon atoms; or OH group-containing aromatic aliphatic hydrocarbonhaving 7 to 10 carbon atoms.

It is preferable to use the cobalt catalyst and promoter in a ratiobetween about 1:0.01 and about 1:100.

An appropriate solvent is used in the hydroesterification in thepresence of alcohol. The hydroesterification is carried out at atemperature from about 30 to about 150° C., preferably from about 40 toabout 120° C. and at the CO pressure from about 50 to about 3000 psig,preferably from about 100 to about 1500 psig.

The epoxide derivative usable in this invention is shown as thefollowing formula (II):

wherein R₁ and R₂ independently are hydrogen; linear aliphatichydrocarbon having 1 to 20 carbon atoms; branched aliphatic hydrocarbonhaving 3 to 20 carbon atoms; saturated cycloaliphatic hydrocarbon having3 to 20 carbon atoms; cycloaliphatic hydrocarbon having 3 to 20 carbonatoms; aromatic aliphatic hydrocarbon having 7 to 20 carbon atoms;hydrocarbon having 1 to 20 carbon atoms in which a hydrogen on thecarbon chain is substituted with F, Cl or Br; aromatic hydrocarbonhaving 6 to 20 carbon atoms with no substituted group; or aromatichydrocarbon having 6 to 20 carbon atoms in which a hydrogen on thearomatic ring is substituted with F, Cl, an amine group, a nitrilegroup, or an alkoxy group.

Particular preferred examples of epoxide derivatives useful according tothe invention include ethylene oxide, propylene oxide, 1-butene oxide,1-pentene oxide, 1-heptene oxide, 1-octene oxide, 1-nonene oxide,1-decene oxide, 2-methyl-propylene oxide, 2-methyl-1-butene oxide,2-methyl-1-octene oxide, 2-methyl-nonene oxide, 2-methyl-1-decene oxide,2-methyl-1-butene oxide, 2-methyl-1-pentene oxide, 2-methyl-1-hexeneoxide, 2-ethyl-1-heptene oxide, 2-ethyl-1-octene oxide, 2-ethyl-1-noneneoxide, 2-ethyl-1-decene oxide, epifluorohydrin, epichlorohydrin,epibromohydrin, glycidol, methyl glycidate, ethyl glycidate, t-butylglycidate, allyl benzene oxide, styrene oxide, etc.

The alcohol of the present invention is expressed by R′OH. Here, R′ is asaturated linear hydrocarbon having 1 to 20 carbon atoms; an unsaturatedlinear hydrocarbon having 2 to 20 carbon atoms; a branched hydrocarbonhaving 3 to 20 carbon atoms; a cyclohydrocarbon having 3 to 20 carbonatoms; an aromatic hydrocarbon having 6 to 20 carbon atoms; or a linearhydrocarbon including an aromatic group. Preferably R′ is methyl, ethyl,isopropyl, cyclohexyl, phenyl or benzyl.

The solvent of the present invention can be an ether, a substitutedaromatic compound, or an acetate. Of course, the alcohol itself can beused as a solvent.

The ethers useful according to the invention include those representedby the following formulas (III), (IV) and (V):

where R₃, R₄, R₅, R₆, and R₇ independently are saturated aliphatichydrocarbon having 1 to 10 carbon atoms and having no branches; branchedaliphatic hydrocarbon having 3 to 10 carbon atoms; saturatedcyclohydrocarbon having 3 to 10 carbon atoms; cycloaliphatic hydrocarbonhaving 3 to 10 carbon atoms; or aromatic aliphatic hydrocarbon having 7to 10 carbon atoms; m is an integer of 1 to 10; and n is an integer of 2to 5.

Substituted aromatic compounds useful according to the invention includethose represented by the following formula (VI):

where R₈, R₉, R₁₀, R₁₁, R₁₂ and R₁₃ independently are hydrogen;saturated aliphatic hydrocarbon having 1 to 4 carbon atoms and having nobranches; branched aliphatic hydrocarbon having 3 or 4 carbon atoms; F;Cl; or alkoxy group having 1 to 3 carbon atoms.

3-hydroxyesters and derivatives thereof are obtained throughhydroesterification of the epoxide derivative. The 3-hydroxyesters andderivatives thereof afforded according to the present invention arerepresented by the following formulas (VII) and (VIII):

where R₁ and R₂ independently are hydrogen; linear aliphatic hydrocarbonhaving 1 to 20 carbon atoms; branched aliphatic hydrocarbon having 3 to20 carbon atoms; saturated cycloaliphatic hydrocarbon having 3 to 20carbon atoms; cycloaliphatic hydrocarbon having 3 to 20 carbon atoms;aromatic aliphatic hydrocarbon having 7 to 20 carbon atoms; hydrocarbonhaving 1 to 20 carbon atoms in which a hydrogen on the carbon chain issubstituted with F, Cl or Br; aromatic hydrocarbon having 6 to 20 carbonatoms with no substituted group; or aromatic hydrocarbon having 6 to 20carbon atoms in which a hydrogen on the aromatic ring is substitutedwith F, Cl, an amine group, a nitrile group, or an alkoxy group, and R′is a saturated linear hydrocarbon having 1 to 20 carbon atoms, anunsaturated linear hydrocarbon having 2 to 20 carbon atoms, a branchedhydrocarbon having 3 to 20 carbon atoms, a cyclohydrocarbon having 3 to20 carbon atoms, an aromatic hydrocarbon having 6 to 20 carbon atoms, ora linear hydrocarbon including an aromatic group.

As shown in formulas (VII) and (VIII), the 3-hydroxyesters andderivatives thereof are difunctional so as to be available as anintermediate for synthesizing an organic compound or for a coatingmaterial.

The reaction product and solvent are separated from the catalyst andpromoter. The separation of the reaction product and solvent preferablyis carried out by vacuum distillation or by extracting into water, whichwill depend on the solvent. When an ether of Formula (III) or asubstituted aromatic compound of Formula (IV) is used as solvent, thereaction product of 3-hydroxyester derivative is extracted into water.When an ether of Formula (IV) or (V) or a lower alcohol such as methylalcohol, ethyl alcohol or isopropyl alcohol is used as solvent, thereaction product is separated under vacuum distillation. When a higheralcohol than isopropyl alcohol is used as solvent, the reaction productis separated by extracting into water. When extracting into water, the3-hydroxyesters and derivatives thereof are extracted into the waterlayer by adding water at about 100° C. or lower to the reactionproduction mixture in the presence of carbon monoxide at a pressure fromabout 20 to about 3000 psig.

The extracts react with hydrogen at a temperature from about 30 to about350° C. and at a pressure from about 50 to about 5000 psig in thepresence of a catalyst system for hydrogenation to prepare ahydrogenation product mixture including a 1,3-alkanediol. In thisinvention, this step is called “hydrogenation”. The hydrogenation can becarried out without extraction of the reaction products. The separatedcatalyst and promoter can be recycled to the hydroesterification step inpart or in total.

The 3-hydroxyester derivative is hydrogenated in the presence of acatalyst system to produce a 1,3-alkanediol. The catalyst system for thehydrogenation preferably includes copper chromate or Pd/C.

The hydrogenation process preferably is carried out at a temperaturefrom about about 50 to about 250° C. and at a pressure from about 200 toabout 3000 psig.

Finally, the 1,3-alkanediol is recovered from the hydrogenation productmixture. The separation and hydrogenation of the reaction product can beeasily carried out by an ordinary skilled person in the art to which thepresent invention pertains.

The present invention is further illustrated by the followingnon-limiting examples.

EXAMPLES Examples 1-10 Hydroesterification of Ethylene Oxide withCatalyst of Co₂(CO)₈ in Imidazole

At room temperature, a 450 ml Parr reactor was filled with methanol and5 mmole of Co₂(CO)₈. The reactor was filled with CO gas at 500 psig,heated to 80° C. and agitated for one hour. Then the reactor was cooledto room temperature and imidazole as promoter was added to the reactor.Ethylene oxide was added to the reactor and CO was added at apredetermined pressure. The reactor was heated to a temperature as shownin Table 1 at a pressure as in Table 1 for the time as in Table 1.During the reaction, the reaction product was sampled using a tube. Asproduct, methyl 3-hydroxypropionate (3-HPM) was analyzed with a GC. Thereaction conditions and the resulting data are shown in Table 1.

Imidazole of 20 mmole as promoter was used in Examples 1-7 and 9, 40mmole in Example 8, and 30 mmole in Example 10. Ethylene oxide of 500mmole was used in Examples 1-8 and 10, and 1.4 mmole in Example 9. InExample 7, tetraglyme was used besides methyl alcohol.

TABLE 1 Yield¹⁾ Me Conv. (%) Selectivity (mole %) Temp. Press. Time OHRate 3- 3- Ex. ° C. (bar) (hrs) (ml) (%) HPM HPM²⁾ AA³⁾ DMA⁴⁾ ME⁵⁾Dimer⁶⁾  1 70 34 3 200 78.0 65.6 84.8 2.71 9.44 1.10 2.66 9 6 0  2 70 503 200 68.2 59.6 87.4 7.77 0.20 2.38 2.17 3 8 7  3 70 80 3 200 65.6 58.689.3 4.50 0.59 2.47 3.11 6 5 3  4 60 50 3 200 45.1 40.2 88.9 8.45 0.392.19 0 9 0 6  5 75 50 3 200 78.6 66.0 83.9 0.03 10.9 1.92 3.10 2 1 7 8 6 80 50 3 200 91.6 71.8 78.4 9.44 6.51 2.63 2.97 1 6 5  7 80 34 2 100 —82.4 — — — — — 4  8 80 34 4 250 — 70.1 — — — — —  9 80 34 4 200 — 66.4 —— — — — 10 75 60 3 150 95.2 88.9 93.3 1.78 0.32 0.98 3.61 7 0 1 Notes:¹⁾Yield = Selectivity × Conversion rate ²⁾3-HPM: methyl3-hydroxypropionate (3hydroxypropionic acid methyl ester) ³⁾AA:acetaldehyde ⁴⁾DMA: acetaldehyde dimethyl acetal ⁵⁾ME: methoxy ethanol⁶⁾Dimer: HOCH₂CH₂C(O)OCH₂CH₂(O)OCH₃

Comparative Examples 1-2 Hydroesterification of Ethylene Oxide withCatalyst of Co₂(CO)₈

Comparative Example 1 was conducted in the same manner as in Example 1except that 4 mmole of 3-hydroxypyridine was used as promoter instead ofimidazole and except the reaction conditions. 1 mmole of Co₂(CO)₈ wasused and 200 mmole of ethylene oxide was used. The reaction conditionsof Comparative Example 1 were shown in Table 2.

Comparative Example 2 was conducted in the same manner as in Example 1except that Co₂(CO)₈ as catalyst was used without any catalyst promoter.2.5 mmole of Co₂(CO)₈ was used and 650 mmole of ethylene oxide wasused.The reaction conditions of Comparative Example 2 were shown inTable 2. the resulting data were shown in Table 2.

In Comparative Example 1 using a pyridine derivative, 3-HPM was obtainedin a high yield, but by-products such as acetaldehyde were produced in asignificant amount. In Comparative Example 2 not using a catalystpromoter, the yield of 3-HPM was very low.

TABLE 2 Yield¹⁾ Me Conv. (%) Selectivity (mole %) C. Temp. Press. TimeOH Rate 3- 3- Ex. ° C. (bar) (hrs) (ml) (%) HPM HPM²⁾ AA³⁾ DMA⁴⁾ ME⁵⁾Dimer⁶⁾ 1 75 60 4  40 92.0 81.0 88.0 8.43 — 2.28 1.22 7 8 7 2 75 60 4120 — 20.6 — — — — — Notes: ¹⁾Yield = Selectivity × Conversion rate²⁾3-HPM: methyl 3-hydroxypropionate (3-hydroxypropionic acid methylester) ³⁾AA: acetaldehyde ⁴⁾DMA: acetaldehyde dimethyl acetal ⁵⁾ME:methoxy ethanol ⁶⁾Dimer: HOCH₂CH₂C(O)OCH₂CH₂(O)OCH₃

Examples 11-14

Examples 11-14 were conducted in the same manner as in Example 1 exceptfor use of the epoxide derivative. As shown in Table 3, in Examples11-14, propylene oxide, butylenes oxide, epichlorohydrin, and glycidolas epoxide derivative were used, respectively. 5 mmole of Co₂(CO)₈, 10mmole of catalyst promoter, 500 mmole of epoxide derivative, and 200 mlof ethyl alcohol as solvent were used. The reactor was kept at 80° C.and at 34 bar for 4 hours. The products and yields of Examples 11-14 areshown in Table 3.

TABLE 3 Example Epoxide Product Yield (%) 1 Propylene Methyl3-hydroxybutanoate 60.56 oxide 2 Butylene oxide Methyl3-hydroxypentanoate 53.70 3 Epichlorohydrin Methyl 3-hydroxy-4- 66.17chlorobutanoate 4 Glycidol 3-hydroxy-γ-butyrolactone 62.50

Example 15

1 g of 3-hydroxypropionate was added to a 45 ml Parr reactor togetherwith 10 ml of methyl alcohol as a solvent for the 3-hydroxypropionate.0.5 g of copper chromate was added to the reactor as a catalyst.Hydrogen was introduced to the reactor at 1500 psig and the reactor wasagitated and heated to 180° C. After reaction for 15 hours, the reactorwas cooled to room temperature. The product was analyzed with a GC.Conversion rate to 3-hydroxypropionate was about 5%, and selectivity to1,3-propandiol was about 3%.

Examples 16-36

The following additional reactions were carried out using the promotersindicated:

TABLE 4 Conv. Rate Selectivity (mole %) Ex. Promoter (%) AA DMA ME HPMDD¹⁾ Dimer 16 Imidazole²⁾ 94 2.0 0.5 1.2 78 1.7 13 17 Pyrimidine 90 3.40.1 4.4 91 0.3 1.0 18 Pyridizine 81 1.7 2.2 2.4 91 0.5 2.1 19 2-amino-59 39 0.7 3.6 57 0.7 0.9 pyrimidine 20 Amino- 62 36 0.5 2.3 40 0.4 0.8pyrazine 21 3-amino- 39 21 0 5.3 73 1.2 0 1,2,4-triazine 22 1-(3- 87 3.20 3.1 87 6.3 0 amino- propyl) imidazole 23 2,4-diamino- 55 37 0 4.2 610.2 0 6-methyl- 1,3,5-triazine 24 Dimethyl- 55 37 0 4.2 61 0.2 0 amine25 Tetramethyl- 47 3.6 57 5.0 34 0.5 0 pyrazine 26 3- 64 5.9 1.1 9.2 776.0 0.9 (dimethyl- amino- methyl) indole 27 2-pyridyl- 64 2.1 0.4 2.9 931.8 0 carbinol 28 3-pyridine- 71 5.6 0 6.3 85 0.5 2.1 propanol 295-amino-1- 53 3.1 0.1 7.4 89 0 0 naphthol 30 1-(2- 59 39 0.7 3.6 52 0.70.9 hydroxy- ethyl) pyrrolidine 31 3-hydroxy- 54 1.9 0 1.0 94 3.5 0quinone 32 1-hydroxy- 78 34 0 6.1 57 1.1 1.3 benzotriazole hydrate 332-mercapto- 74 44 0 3.4 51 0.2 1.8 pyridine 34 2-mercapto- 57 37 0.6 5.053 0.5 4.1 benzimida- zole 35 2,2′- 69 37 0.3 2.0 58 2.6 0 biquinoline36 2,3-bis(2- 58 13 0.2 27 54 4.6 0.8 pyridyl) pyrazine Notes: ¹⁾DD:dehydrated dimer = CH₂CHC(O)O CH₂CHC(O)O OH₃ ²⁾Reaction conditions ofExample 16: MeOH = 40 L, Co₂(CO)₈ = 2.72 mol, imidazole = 5.45 molEthylene oxide = 0.272 Kmol Reaction temperature = 80° C. CO pressure =70 bar Reaction time = 4 hours ³⁾Reaction conditions of Examples 17-36:MeOH = 200 ml, Co₂(CO)₈ = 5 mmol, promoter = 20 mmol Ethylene oxide =500 mmol Reaction temperature = 80° C. CO pressure = 70 bar Reactiontime = 4 hours Residual product: methyl acetate, ethylene glycol,unknowns

Examples 37-38

The following examples illustrate the differences arising from use ofstructural isomers of hydroxypyridine as a promoter:

TABLE 5 Conv. Rate Selectivity (mole %) Ex. Promoter (%) AA DMA ME HPMDD Dimer 37 3-hydroxy- 72 1.8 0.3 2.5 91 1.0 3.3 pyridine 38 2-hydroxy-64 2.1 0.4 2.9 93 1.8 0 pyridine

The present invention provides a novel process for preparing a1,3-alkanediol, in which a 3-hydroxyester is prepared in a high yield byreacting an epoxide derivative with an alcohol and carbon monoxide inthe presence of a catalyst system including a cobalt catalyst and apromoter, in particular an imidazole or a derivative thereof . Further,the present invention provides a process for preparing a 1,3-alkanediolat a lower cost by using an imidazole or a derivative thereof aspromoter.

It should be apparent to those ordinarily skilled in the art thatvarious changes and modifications can be made without departing from thescope of the present invention.

What is claimed is:
 1. A catalyst system comprising a mixture of acobalt catalyst and a promoter selected from the group consisting ofimidazole, pyrrole, pyrazine, pyrimidine, derivatives thereof, andmixtures thereof.
 2. The catalyst system as claimed in claim 1, whereinsaid cobalt catalyst is Co₂(CO)₈.
 3. The catalyst system as claimed inclaim 2, wherein said promoter is represented by the following formula(I):

wherein R₁₄, R₁₅, R₁₆, and R₁₇ independently are hydrogen, branchedaliphatic hydrocarbon having 3 to 10 carbon atoms; linear aliphatichydrocarbon having 1 to 10 carbon atoms; saturated cyclohydrocarbonhaving 3 to 10 carbon atoms; cycloaliphatic hydrocarbon having 3 to 10carbon atoms; aromatic aliphatic hydrocarbon having 7 to 10 carbonatoms; F; Cl; alkoxy having 1 to 3 carbon atoms; OH; OH group-containingbranched aliphatic hydrocarbon having 3 to 10 carbon atoms; OHgroup-containing linear aliphatic hydrocarbon having 1 to 10 carbonatoms; OH group-containing saturated cyclohydrocarbon having 3 to 10carbon atoms; OH group-containing cycloaliphatic hydrocarbon having 3 to10 carbon atoms; or OH group-containing aromatic aliphatic hydrocarbonhaving 7 to 10 carbon atoms.
 4. The catalyst system as claimed in claim1, wherein the promoter is imidazole.
 5. The catalyst system as claimedin claim 1, wherein the promoter is pyrimidine.
 6. The catalyst systemas claimed in claim 1, wherein the promoter is pyrrole.
 7. The catalystsystem as claimed in claim 5, wherein the promoter is 2-aminopyrimidine.8. The catalyst system as claimed in claim 1, wherein the promoter isaminopyrazine.
 9. The catalyst system as claimed in claim 4, wherein thepromoter is 1-(3-aminopropyl)imidazole.